Heartworm In Dogs: Signs, Treatment And Prevention

Heartworm is a potentially serious disease spread by mosquitoes, making prevention particularly important for dogs living in warm Queensland environments. Whether you are new to dog ownership or have recently moved to the Mackay region, a vet clinic in Sarina can help establish an appropriate prevention routine before infection has a chance to develop.

What Is Heartworm And How Do Dogs Get It?

Heartworm disease is caused by the parasite Dirofilaria immitis. Dogs become infected through the bite of an infected mosquito — not directly from another dog.

When a mosquito feeds on an infected animal, it can pick up immature heartworms known as microfilariae. These develop inside the mosquito before being passed to another dog during a later bite. Once inside the new host, the larvae continue developing and can eventually become adult worms associated with the heart and pulmonary blood vessels.

This answers a common question about how dogs get heartworm in Australia: mosquito exposure is the essential part of the transmission cycle.

That means even dogs that spend most of their time indoors are not completely protected. A single infected mosquito can enter a home or bite a dog while it is outside.

Signs And Symptoms To Watch For

One of the difficulties with heartworm is that an infected dog may show few or no obvious symptoms during the earlier stages. Signs can become more noticeable as infection progresses and the heart and lungs come under greater strain.

Possible signs of heartworm in dogs include:

• A persistent cough
• Reduced willingness or ability to exercise
• Tiredness or weakness
• Weight loss
• Breathing difficulties
• A swollen or distended abdomen
• Collapse in severe cases



These symptoms can also occur with many other health conditions, so they should not be treated as proof of heartworm.

A dog with coughing, reduced exercise tolerance or unexplained weakness should be assessed by a veterinarian rather than waiting to see whether the problem resolves on its own. Severe breathing difficulty or collapse requires urgent veterinary attention.

How Common Is Heartworm In Queensland?

There is no single current percentage that accurately describes how common heartworm is in dogs in Australia. Risk varies by region, mosquito exposure, preventive treatment and the population being studied.

Heartworm has long been recognised in Queensland, and recent research confirms that infection continues to occur in the state. Studies have also found substantial geographic differences, with northern Queensland populations generally showing greater risk than southern areas. Importantly, studies involving shelter or surrendered dogs should not be assumed to represent the prevalence among all owned dogs.

For dog owners around Sarina and Mackay, the practical takeaway is that heartworm has not disappeared simply because effective preventatives are available.

Warm conditions and mosquito activity mean heartworm in dogs around Sarina and heartworm in dogs around Mackay remains something owners should actively prevent rather than waiting for symptoms.

Regular prevention is especially important because reducing mosquito bites alone cannot provide dependable protection.

Diagnosis And Treatment Options

Heartworm infection is commonly investigated with blood testing. Antigen testing is an important diagnostic tool because it can detect proteins associated with adult female heartworms, while additional blood tests or diagnostic imaging may sometimes be needed depending on the dog and the results.

Testing also has limitations in very early infection because it takes time for larvae to develop into mature worms. This is one reason veterinary advice is important if a dog has missed preventative doses or has an uncertain prevention history.

Heartworm treatment for dogs is more involved than routine prevention.

Once infection is confirmed, treatment may need to address adult worms as well as immature stages, while the dog's heart and lung health also needs to be considered. Activity restriction forms an important part of treatment because complications can occur as adult worms die and are broken down by the body. Treatment protocols are therefore determined by a veterinarian based on the individual dog rather than attempted at home.

If a dog's prevention has lapsed, do not simply restart medication without advice. A vet in Sarina can determine whether testing is appropriate first and recommend how to restart protection safely.

Why Prevention Is Easier Than Treatment

Preventing heartworm is considerably simpler than managing an established infection.

Preventative medications target immature stages before they mature into adult heartworms capable of causing significant cardiovascular and respiratory disease. Consistency is essential because gaps in protection can leave a dog exposed. Year-round prevention is generally recommended rather than trying to predict exactly when mosquito transmission will occur.

Depending on the product and the individual dog, prevention may be available in oral, topical or longer-acting injectable forms. The appropriate choice depends on factors such as age, health, lifestyle and whether previous doses have been missed.

Dog owners should also remember that parasite prevention involves more than heartworm. Fleas, ticks and intestinal worms create different risks and require their own appropriate prevention strategies.

For another aspect of everyday pet safety, see this guide to common pet poisoning and how to prevent it.

Getting Your Dog On A Prevention Plan

The best time to establish heartworm prevention for dogs is before there is a problem.

Puppies can generally begin suitable preventative medication from a young age, while older dogs with an uncertain history may require testing before starting or restarting a program. The exact schedule depends on the product being used, so the manufacturer's directions and veterinary recommendations should always be followed.

If you have recently adopted a dog, moved to the Mackay region or cannot remember when the last heartworm dose was given, make an appointment with a vet clinic in Sarina rather than guessing.

Keeping a prevention plan simple can also improve consistency. Calendar reminders, recurring appointments or choosing an appropriate longer-lasting option can reduce the chance of accidentally missing coverage.

Protect Your Dog From Heartworm

At Sarina Veterinary Surgery, we can help establish the heartworm prevention Sarina dog owners need based on their pet's age, health and current prevention history. Our vet in Sarina can also advise whether testing is appropriate before beginning or restarting treatment.

If you are unsure when your dog's last heartworm prevention was given, contact our team to discuss the safest next step.

Frequently Asked Questions